$ { \left[\begin{array}{r}{3} \\ {-2} \\ {-1}\end{array}\right]+\left[\begin{array}{r}{-2} \\ {3} \\ {-1}\end{array}\right] = {?} } $
Answer: To find the sum of two matrices, add the corresponding items between each matrix. ${\left[\begin{array}{r}{3}+{-2} \\ {-2}+{3} \\ {-1}+{-1}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{r}{1} \\ {1} \\ {-2}\end{array}\right]}$